Formation fluid-sampling apparatus



Nov. 14, 1937 H, J. URBANOSKY FORMATION FLUID SAMPLING APPARATUS 3 Sheets-Sheej. 1

Filed March 8, 1965 f/ara/a J (/no/oaky INVENTOR.

' Affifi A// Nov. 14, 1987 H. J. URBANOSKY FORMATION FLUID SAMPLING APPARATUS Filed March 8, 1965 3 heets-Sheet 2 //Z 76 J 5 79 Q 7L INVENTOR.

United States Patent 3,352,361 FORMATION FLUID-SAMPLING APPARATUS Harold J. Urbanosky, Houston, Tex., assignor to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed Mar. 8, 1965, Ser. No. 437,827 20 Claims. (Cl. 166-100) ABSTRACT OF THE DISCLOSURE This disclosure describes formation fluid-sampling apparatus that includes a tubular probe member adapted for movement into sealing engagement with an adjacent earth formation to obtain samples of connate or formation fluids, if any, therein. If the formation being sampled is unconsolidated, the probe advances into the formation as loose particles therefrom enter the open forward end of the probe. To prevent loss of the sealing engagement, a tubular filter in the probe is arranged to capture any formation particles entering the probe and allow connate fluids to flow on through the filter into a sample chamber on the apparatus. A slidable piston member releasably secured in front of the filter is adapted to be released as the filter moves forwardly to close a normally-open bypass passage between the filter and forward end of the probe, with the piston moving on back through the filter to wipe its internal surfaces of residual borehole fluids.

Accordingly, as will become apparent, it will be seen that this invention relates to new and improved fluid-sampling apparatus; and, more particularly, to sample-taking apparatus for obtaining a sample of connate fluids from particularly soft earth formations traversed by a well bore.

Heretofore, where it was desired to obtain fluid samples from particularly soft or unconsolidated earth formations, fluid-sampling apparatus such as that disclosed in the Brieger Patent No. 2,965,176 has been employed. The tool described in that patent includes an elastomeric sealing member that is selectively urged against the wall of a borehole and held there in sealing engagement to isolate a portion of the wall. Upon command from the surface, a movable tubular probe or so-called snorkel is then extended through an opening in the engaged sealing member and forced into the formation. By opening a selectively operable valve in the tool, a discrete volume of whatever recoverable connate fluids there may be in the formation is expelled by formation pressure through the snorkel into the atmospheric chamber carried on the tool. After a desired amount of fluid is obtained, a second valve is actuated to close the sample-receiving chamber and the snorkel is retracted. The tool is then retrieved to the surface of the ground where the fluid sample is examined.

It will be recognized that as connate fluids are expelled from a particularly soft or unconsolidated formation, formation particles, such as sand, may be carried along by the flow and deposited in the sample-receiving chamber. In the Brie'ger apparatus, this undesirable action is minimized by progressively advancing the snorkel into the formation as particles are washed out thereby reinforcing the loose formation. It will be appreciated, however, that once the snorkel has advanced to its outer limit of travel, the continued washing away of particles will quickly create a large void that will extend beyond the periphery of the sealing member. Once this occurs, the sealing member will no longer be sealed against the formation and the well control fluid will be admitted through the snorkel into the sample-receiving chamber. Thus, to reduce the rate at which particles are washed away, it has been found to be necessary in that tool to regulate the flow rate at which fluid samples are admitted by arranging a slidable piston within the sample-receiving chamber to slowly displace a volume of water through an orifice into an atmospheric chamber as the fluid sample is being received on the op posite side of the piston.

Although these and other measures have improved the odds of obtaining fluid samples from unconsolidated formations, there are still some problems arising in the use of such equipment. For example, since it is necessary to limit the flow rate at which a sample is obtained, the fluid-sampling apparatus must be held in position for per haps an hour. Such long waits often make it necessary to steadily reciprocate the suspension cable to prevent it from becoming stuck in the well as by differential sticking or key-seating. Moreover, an extended testing cycle will expend valuable rig time as Well as reduce the number of operations that can be conducted during an allotted time. It will also be understood that more than one-half of the sample-receiving chamber is used to contain the water cushion. Thus, with a given size of tool, to obtain a partic ular volume of connate fluids, the overall length of the sample-receiving chamber must be more than double. It is apparent, of course, that it is not particularly desirable for many reasons to have greatly elongated well tools.

Accordingly, it is an object of the present invention to provide new and improved sampling apparatus for obtaining fluid samples from soft or unconsolidated earth formations wherein the amount of formation particles that are carried along with a fluid sample is greatly reduced.

Another object of the present invention is to provide new and improved fluid-sampling apparatus that is capable of taking fluid samples at high flow rates while still maintaining the sealing member in sealing engagement with the formation.

Still another object of the present invention is to provide new and improved fluid-sampling apparatus that does not require a space-consuming water cushion in the sample receiving chamber and can obtain a fluid sample more quickly than apparatus of the prior art.

These and other objects of the present invention are provided by operatively arranging filtering means with a tubular probe adapted to be placed in fluid communica tion with an earth formation. A slidable wiping member is arranged between the probe and upstream surface of the filtering means to be urged along the filtering means by incoming connate fluids to wipe the surface and isolate the incoming fluids from residual well control fluids in the probe so that the influent fluids will pass through the cleaned filtering means for collection in a sample-receiv ing chamber and any entrained particles in the influent will be trapped within the probe.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of opera tion together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIG. 1 depicts sample-taking apparatus employing the principles of the present invention as it might appear with in a well bore;

FIG. 2 is a simplified, schematic representation of the apparatus illustrated in FIG. 1;

FIG. 3 is a cross-sectional view of a portion of typical apparatus employing the present invention;

FIG. 4 is an enlarged cross-sectional view of a portion of the apparatus depicted in FIG. 3;

FIG. 5 is a somewhat simplified cross-sectional view of a portion of the apparatus shown in FIG. 3 and illustrating one condition of operation; and

FIG. 6 is a view, similar to FIG. 5, and illustrating still another condition of operation.

Turning now to FIG. 1, fluid-sampling apparatus 10.

3 incorporating the principlesof the present invention is shown suspended from a multi-conductor cable 11 in a well bore 12 containing a well control fluid 13 and positioned adjacent a particular earth formation 14 for collecting a sample of connate fluid from that formation. The cable 11 is spooled from a winch 15 at the earths surface with some of its conductors being connected to a switch 16 for selective connection to a power source 17 and others being connected ,to indicating-and-recording apparatus 18. The fluid-sampling apparatus 10 includes an upper and lower housing section 19, 20 that are tandemly mounted above and below a testing section 21 having sample-admitting means 22 and 23 spaced along one side thereof and extendible wall-engaging means 24 on the opposite side. In the position illustrated in FIG. 1, the wall-engaging means 24 has been extended to laterally shift the fluid-sampling apparatus 10 in the well bore 12 and sealingly engage the sample-admitting means 22 and 23 against the exposed face of the formation 14 in preparation for obtaining a sample of connate fluids therein.

Inasmuch as the particular details of certain components are not necessaryfor full understanding of the present invention, the fluid-sampling apparatus 10 is shown only schematically in FIG. 2 to illustrate the overall relation of the apparatus to the particular sample-admitting means 23 of the present invention. Accordingly, these other components may Well be those described in greater detail in the Desbrandes Patent No. 3,011,554 and the Whitten Patent No. 3,261,402, filed as a continuation of a copending application by Frank R. Whitten, Ser. No. 384,024, filed July 13, 1964, now abandoned; and their description will be limited to only what is necessary for understanding their basic operation and general relationship to one another and to the present invention.

As illustrated in FIG. 2, the fluid-sampling apparatus 10 is basically comprised of a hydraulic system 25 which utilizes the hydrostatic pressure of the well control fluid to develop an increased hydraulic pressure for actuating the apparatus and a sample-collecting system 26 for obtaining a sample of connate fluids. After the apparatus 10 has been positioned adjacent a formation, the hydraulic system 25 is activated from the surface. The Wallengaging means 24 are extended to laterally shift the apparatus 10 and sealingly engage the sample-admitting means 22, 23 against the formation for obtaining a fluid sample.

Once a sample has been collected in a sample-receiving chamber 27, the chamber is closed and pressure in the hydraulic system 25 is relieved to disengage the wall-engaging means 24 and sample-admitting means 22, 23 for retrieval of the apparatus 10.

The hydraulic system 25 is generally of the type described in the Desbanrdes patent, supra, and includes a master piston 28 slidably mounted in a stepped cylinder 29 in the upper section 19. An electrically actuated mud valve 30, such as shown in FIG. 4 of the Desbrandes patent, is selectively operable to admit the well control fluid 13 through a passage 31 into an enlarged-diameter portion 32 of the cylinder 29 above the piston 28. Thus, whenever the mud valve is opened, the hydrostatic pressure of the well control fluid 13 will drive the master piston 28 inwardly to develop a somewhat greater hydraulic pressure in a reduced-diameter portion 33 of the cylinder 29 below the piston. This developed hydraulic pressure will, of course, be equal to the product of the hydrostatic pressure multiplied by the ratio of the areas of the enlarged end 34 and the reduced end 35 of the piston 28.

A pressure-regulating valve 36, such as the one shown in FIGS. 8 and 8A of Patent No. 3,011,554, supra, responds to the hydrostatic pressure of the well control fluid 13 to maintain the hydraulic pressure in an outlet conduit 37 downstream of the valve 36 at a predetermined differential above the hydrostatic pressure.

The hydraulic system 25 also includes a hydraulic fluid dump chamber 38 that is connected to the hydraulic actuator 39 of a normally-closed, pressure-equalizing valve 40 and (via a normally-closed,electricallyactuated valve 41 such as shown in FIG. 7 of the Desbrandes Patent, supra) to the main hydraulic conduit 37. The dump chamber 38 is normally at atmospheric pressure and is divided into a larger and a smaller compartment 42 and 43 by a partition 44 in which an orifice 45 is mounted. When it is desired to retrieve the apparatus 10, the electrically actuated valve 41 is opened to admit hydraulic fluid from the main conduit 37 into the smaller compartment 43 of the dump chamber 38 and to. the actuator piston 39 of the pressure-equalizing valve 40. Although the hydraulic pressure in the main conduit 37 is immediately reduced somewhat when valve 41 is opened, the lower compartment 43 and orifice 45 are sized to enable the hydraulic actuator 39 to operate and open the equalizing valve 40 before the hydraulic pressure has dropped to its final level.

The pressure-equalizing valve 40 is actuated by the actuator piston 39 which has a protruding stop 46 and is slidably received within an enlarged-diameter portion 47 of a stepped cylinder 48. The reduced-diameter portion 49 of the cylinder 48 receives the slidable piston valve 40 which has a rearwardly extending projection 50 that is normally engaged against the forward face of the actuator piston 39. In its normal position as illustrated in FIG. 2, the valve member 40 blocks fluid communication from the sample-collecting system 26 and a conduit 51 opening to the exterior of the apparatus 10. Thus, it will be appreciated that whenever hydraulicfluid is admitted through valve 41 to the dump chamber 38, the actuator 39 will shift the equalizing valve 40 outwardly to open fluid communication between conduits 51 and 52.

The extendible wall-engaging means 24 on the opposite side of the testing section 21 from the sample-admitting means 22 and 23 is arranged to shift the apparatus 10 laterally in a well bore before fluid samples are taken. The hydraulically actuated wall-engaging means 24 is comprised of an extendible back-up shoe 53 which is normally held in a retracted position by springs 54 and 55 against the apparatus 10. A piston actuator 56 is slidably received within a hydraulic cylinder 57 that is connected by a conduit 58 to the main hydraulic conduit 37. Thus, Whenever the mud valve 30 is opened, the increased pressure in the main conduit 37 will urge the piston actuator 56 outwardly to extend the back-up shoe 53 against the exposed adjacent face of'the formation.

The testing section 21 .carries the sample-admitting means 23 of the present invention andmay also include alternate sample-admitting means 22 such as that shown at 21 in the aforementioned Whitten patent. The sample-admitting means 22,. 23 include longitudinally spaced lateral chambers 59 and 60 within the testing section 21 that are open at one end, with packing means, such as annular elastomeric sealing members 61 and 62, being mounted outside of the section around these openings to provide central openings 63 and 64 for admitting fluid samples into the chambers. The chambers 59 and 60 are interconnected by a conduit 65 and normally-closed passage means, such as a normally-closed electrically actuated valve 66 connected to the sample-receiving chamber 27 by a conduit 67. The conduit 52 connects the chambers 59 and 60 to the normally-closed pressureequalizing valve 40.

As described in greater detail in the aforementioned Whitten patent, a shaped charge 68 is disposed in the rear of the upper chamber 59. A first thin-walled closure member 69 is mounted in front of the shaped charge 68 to fluidly seal the shaped charge within the rearward portion of the chamber 59. A second thin-walled closure member 70 is disposed adjacent to and blocks the central opening 63 through the annular sealing member 61. The shaped charge 68 is connected to electrically responsive igniter means, such as a detonating cord 71 and a blasting cap 72, that is ignitable from the surface via a conductor 72a in the cable 11. Thus,.it Willbe appreciated that so long as it has not been detonated, the shaped charge 68 will be isolated from the samplecollecting system 26 and fluids can enter the testing section 21 only by way of sample-admitting means 23.

Generally stated, the sample-admitting means 23 of the present invention includes an actuator piston 73 that is sealingly and slidably mounted in the rear of the lower chamber 60 and adapted to urge a tubular probe 74 and a coaXially received filtering tube 75 forwardly in the sample chamber through the central opening 64 in the sealing member 62.

For delaying the operation of the sample-admitting means 23 until the wall-engaging means 24 has shifted the apparatus against the formation, an accumulator chamber 76 and orifice 77 are provided to delay the operation of the actuator piston 73. A slidable piston 78 is sealingly disposed in the accumulator chamber 76 and is normally urged inwardly therein by the hydrostatic pressure of the well control fluid. The enclosed space 79 between the piston 78 and rear wall of the chamber 76 is then connected by a branch conduit 80 to the cylinder 60 at the rear of the actuator piston 73, with another conduit 81 having the orifice 77 connecting the branch conduit to the main hydraulic conduit 37.

The sample-receiving chamber 27 in the lower section has a hydraulically actuated closure or seal valve 82, such as that shown in FIG. 10 of the Desbrandes patent, supra, comprised of an actuator piston 83 slidably disposed in a cylinder 84 and carrying a valve member 85 adapted to engage a complementary valve seat 86 at the entrance of the sample-receiving chamber 27. As shown in FIG. 2, the seal valve 82 is normally held open but, once it has been actuated, it will become latched in a closed position. A normally-closed, electrically actuated valve 87 connects the upper portion of the cylinder 84 to the main hydraulic conduit 37. Thus, to shut off fluid flow from the main fluid conduit 67, opening of the valve 87 will admit hydraulic fluid into the cylinder 84 and shift the valve member 85 downwardly into sealing engagement with the valve seat 86.

Pressure transducers 88 and 89 are provided to continuously monitor the pressures in the hydraulic system and sample-collecting system 26. These transducers 88 and 89 may, for example, be of the type shown in FIG. 9 of the Desbrandes patent, supra, and are connected by electrical leads 88a and 89a to the pressure indicating-and-recording apparatus 18 at the surface of the earth. Thus, by observing the variations of these pressure measurements, a skilled operator will be advised of each step in the operating cycle of the fluid-sampling apparatus 10.

To operate the sample-taking apparatus 10 illustrated in FIGS. 1 and 2, the apparatus is positioned in a well bore or borehole 12 adjacent a particular formation 14 of interests. Then, by connecting the switch 16 to cable conductor a, the mud valve 30 will be opened to admit well control fluid 13 through passage 31 into the upper portion 32 of the master cylinder 29. This will drive the master piston 28 downwardly and develop a substantially greater hydraulic pressure in the reduced-diameter portion 33 of the cylinder. The pressure-regulating valve 36 will operate to admit hydraulic fluid into the main hydraulic conduit 37 and maintain the pressure therein at a substantially constant differential above the hydrostatic pressure of the well control fluid 13.

Since the other normally-closed valves 41 and 87 are not yet opened, the hydraulic fluid in the main conduit 37 will be admitted initially only to conduits 58 and 81 leading to the wall-engaging means 24 and the sampleadmitting means 23, respectively. However, in view of the restrictive effect of the orifice 77 in conduit 81, the piston actuator 56 will operate first and extend the backup shoe 53 against one face of the well bore 12 to shift the apparatus 10 laterally in the opposite direction. Once the apparatus 10 has been shifted laterally, the annular sealing members 61 and 62 will be sealingly engaged against the opposite face of the well bore 12.

Once the hydraulic pressure in the conduit 81 downstream of the orifice 77 has risen above the hydrostatic pressure, it will be realized that the accumulator piston 78 will move outwardly before the actuator piston 73 since the front end of the sample tube 74 is engaged against the formation 14. Moreover, the accumulator piston 78 will be able to move outwardly only as fast as additional hydraulic fluid is discharged through orifice 77 to maintain hydraulic pressure in the accumulator chamber 76. Thus, it will be appreciated that the combined cooperative effect of the orifice 77 and accumulator piston 78 is to delay the operation of the sample-admitting means 23 until the sealing members 61, 62 are tightly sealed against the exposed formation face. It will be understood that by monitoring pressure transducer 88, the operator can determine when the sealing members 61, 62 have been fully engaged.

Once the accumulator piston 78 has reached its final position, the hydraulic pressure behind piston 73 will build-up to extend the sampling tube 74 and filtering tube 75 through the central opening 64 of the sealing member 62 and urge the tubes against the formation 14. Should there be a recoverable and flowable connate fluid therein and the formation 14 is unconsolidated, upon opening of the flow-line valve 66, the tubes 74 and 75 will be forced into the formation as the fluid and loose formation particles flow into the sample-admitting means 23. The loose formation particles will be trapped within the filter tube 75 and the fluid sample will flow into the sample tube 74, pass through conduit 67, and enter the sample-receiving chamber 27. Should, however, the formation 14 be well consolidated so that no particles are washed away, the tubes 74 and 75 will be held against the formation and the fluid sample will flow into the filter tube and on into the chamber 27 It will be appreciated, of course, that whenever the flowline valve 66 is opened, the pressure in the main fluid conduit 67 will be immediately reduced. Thus, by monitoring the pressure in the main fluid conduit 67 by means of pressure transducer 89, a skilled operator can determine whether a fluid sample has entered the samplereceiving chamber 27.

Should there be no fluid sample collected by sampleadmitting means 23, the operator will connect the power source 17 to cable conductor 72a and detonate the shaped charge 68 of the alternate sample-admitting means 22. Upon detonation of the shaped charge 68, the thin-walled closure members 69 and 70 will be punctured and the perforating jet will produce a perforation in the formation. Accordingly, should there be recoverable connate fluids that can flow into the perforation, they will enter the sample-admitting means 22 and flow into the samplereceiving chamber 27 by way of conduits 65 and 67.

Whenever pressure measurements indicate that the sample chamber 27 is most likely full, the power source 17 is connected to cable conductor 87a to open valve 87. Opening of valve 87 will admit hydraulic fluid from the main conduit 37 to the piston actuator 83 of the seal valve 82 and close the sample-receiving chamber 27.

To recover the apparatus 10, the power source 17 is connected to conductor 41a to open valve 41 and relieve the hydraulic pressure holding the apparatus in position. Opening of valve 41 will admit hydraulic fluid to the lower compartment 43 of the dump chamber 38 as well as to cylinder portion 47 behind the piston actuator 39 of the pressure-equalizing valve 40. As previously explained, however, the hydraulic pressure in conduit 90 will decrease slowly so that the actuator 39 will be able to first shift valve member 40 outwardly from its flowblocking position between conduits 51 and 52. Once the -well control fluid 13 is admitted through the cylinder 49 and conduit 51 into the sample chambers 59, 60, the

fluid pressure across the sealing members 61 and 62 will be equalized.

Moreover, as the hydraulic pressure drops in the main conduit37, the hydrostatic pressure of the well control fluid 13 will, with the assistance of springs 54, 55, retract the back-up shoe 53 to free the apparatus and permit it to be retrieved.

Turning now to FIG. 3, a partial cross-sectional view is shown of a preferred embodiment of the testing section 21 employing the sample-admitting means 23 of the present invention and the sample-admitting means 22 of the aforementioned Whitten patent. It is believed, however, that comparison of FIGS. 2 and 3 with the aid of the reference numerals and the preceding description, makes it unnecessary to describe those portions of the testing section 21 which are not a part of the present invention. Thus, the remaining description will be.

directed to the sample-admitting means 23 of the present invention.

The sample-admitting means 23 includes a tubular member 91 that is threadedly engaged in the lateral bore 60 through the body of thesection 21, with an enlargeddiameter forward portion 92 of the member being received within a counterbored recess 93 at one end of the bore. A plurality of transverse passages 94 in the wall of the tubular member 91 provide fluid communication from its axial bore 95 to a circumferential groove 96 around the member. O-rings 97, 98 spaced apart and on both sides of the circumferential groove 96 fluidly seal the tubular member 91 in the lateral bore 60 to make the groove a fluid-tight chamber in the forward portion of the lateral bore that is in communication with the main sample conduit 67 and interconnecting conduit 65 to the other sample-admitting means 22. The extendible sampling tube 74 and filter tube 75 and their piston actuator 73 are slidably received within the axial bore 95 and fluidly sealed therein by O-rings 99 and 100.

The annular sealing member 62 is formed of an elastomeric material and is bonded to the front face of a thin annular plate 101. A plurality of rearwardly extending projections 102 from the sealing member 62 have inwardly directed lips that are received within an annular groove 103 around the periphery of the enlarged portion 92 of the tubular member 91. The forward face 104 of the sealing member 62 is curved at least in the horizontal plane so as to generally conform to the curvature of a well bore. A projecting lug '105 fromthe backing plate 101 is received within a complementary groove in the testing section 21 to align the sealing member 62. An annular member 106 is bonded within the central opening 64 of the sealing member 62 and supports an O-ring 107 for sealingly receiving the forward end 108 of the sampling tube 74 to prevent leakage of well control fluid into the sealed-off space adjacent to central opening 64.

Thus, as will be subsequently described, when the sealing member 62 is sealiugly engaged and a fluid sample is admitted through the central opening 64 of the sealing member 62, it will pass through the filter tube 75 into the sampling tube 74 and into the axial'bore 95 between O-rings 99 and 100. From this point, the fluid sample will flow through the lateral passages 94 and circumferential groove 96 into the main fluid conduit 67 in the testing section 21.

The rearward end of the lateral bore 60 through the testing section 21 is closed by a threadedly engaged cap 109 fluidly sealed by an O-ring 110 and having a cylindrical bore which forms the accumulator cylinder 76 previously described with reference in FIG. 2. The accumulator piston 78 is sealingly received within the cylinder 76 and is free of slide therein between spaced, opposed shoulders 111 and 112.. The accumulator cylinder 76 is in fluid communication through port 80 with that portion of chamber 60 around the rear of the tubular body 91 and between the O-rings 97 and 110.

Turning now to FIG. 4, an enlarged viewis shown of the coaxially arranged sampling tube 74 and filter tube 75 of the present invention. The sampling tube 74 has an enlarged rearward portionthat serves as the piston actuator 73 and is sized for sliding reception in the axial bore through the tubular body 91, with the remainder of the sampling tube being of a uniform. outer diameter and sized for sealing engagement within the O-rings and 107 in the forward portion of the body and Within the sealing member 62. The forward end of the sampling tube 108 is bevelled to ensure that the open end of the tube will make contact with a formation around its entire perimeter.

Lateral ports 113 immediately in front of the enlarged portion 73 provide fluid communication from the annular space 114 between the tubes 74 and '75 to the axial bore 95 through the body 91. The axial bore through the sampling tube 74 is uniform along its intermediate portion 115, with an enlarged-diameter rearward portion 116 and a reduced-diameter forward portion 117 providing rearwardly directed shoulders 118, 119 at the junctions of the bore portions.

A tubular cap member 120 is threadedly engaged within the rearward end of the sampling tube 74 and extends forwardly a short distance. If desired, the bore 121 through the cap member 120 may be hexagonally formed to provide a wrench socket.

The filter tube 75 is comprised of a short enlargeddiameter, rearward portion 122 from which acylindrical piston 123 projects and an elongated forward portion 124 of a slightly smaller diameter. The cylindrical piston 123 is slidably received within the bore 125 of the tubular cap 120 and fluidly sealed therein by an O-ring 126. The junction of the enlarged and reduced tube portions 122, 124 provides a forwardly directed shoulder 127 that is normally a short distance to the rear of and adapted to engage the internal shoulder 118 inside of the sampling tube 74 whenever the filter tube 75 is shifted forwardly.

The forward portion 124 of the filter tube 75 extends into the intermediate bore portion 115 of the sampling tube 74 and terminates within a short distance of the internal shoulder 119 at the forward end of the sampling tube. The forward extremity 128 of the filter tube 75 is sized for snug reception within the reduced bore portion 117 of the sampling tube 74. Thus, whenever the filter tube 75 is shifted forwardly within the sampling tube 74 to where the shoulders 118 and 127 are engaged, the

forward extremity 128 of the filter tube will enter and be snugly fitted within the bore portion 117 of the sampling tube.

The periphery of the forward tube portion 124 is slitted, as at 129, to provide a plurality of elongated, constricted lateral filter openings that will proportionally widen as the pressure differential through the slits increases and expands the tube 75. These slits 129 are carefully formed by partially cutting through the tube wall and then severing the remaining uncut portion so that when the tube 75 is relaxed, the adjacent edges of each slit will be engaged to leave little or no opening. Thus, depending upon such factors as the number of slits 129, their length and the diametrical clearance be tween tubes 74' and 75, the slits will be capable of ex-, panding or widening from their initial separation to a maximumopening whenever tube portion 124 has expanded to the diameter of bore portion 115 of the sampling tube.

Barrier means such as a slidable piston member 130 is received within the generally uniform bore 131 of the filter tube 75 and is fluidly sealed therein by an O-ring 132. In its normal position as seen in FIG. 4, the piston 130 is releasably secured behind an internal shoulder 133 at the forward end of the bore 131 by a frangible washer 134 that projects from the piston over the forward end 9 of the filter tube 75 and is held there by a cap screw 135 threadedly engaged into the piston.

In the position shown in FIG. 4, it will be appreciated that the forward opening or bore portion 117 of the sampling tube 74 is left open to bypass the filter tube 75 to provide normally-open bypass means therearound. Thus, as the fluid-sampling apparatus 10 is being lowered within a well bore, the sample-admitting means 23 is not subjected to pressure differential since the well control fluid is free to enter the sample-admitting means 23 but will, of course, be prevented by the normally-closed flowline valve 66 from entering the sample-receiving chamber 27. This, however, creates no problem inasmuch as the relative volume of the well control fluid entrained above the valve 66 is insignificant in comparison to the total volume of the sample-receiving chamber 27.

Turning now to FIG. 5, a somewhat simplified illustration is shown of the sample-admitting means 23 just before the flow-line valve 66 is opened, At this point in the operating sequence of the fluid-sampling apparatus 10 as previously described in relation to FIG. 2, the mud valve 36 has been opened and hydraulic pressure in the main hydraulic conduit 37 has extended the back-up shoe 53 to sealingly engage the sealing member 62 against the exposed face of the formation 14. Although it was initially retarded by the orifice 77, the hydraulic pressure has now built up within the accumulator chamber 76 and urged the accumulator piston 78 outwardly to the position shown in FIG. 5.

Once the accumulator piston 78 has reached the position shown in FIG. 5, the hydraulic pressure will buildup downstream of orifice 77 and urge pistons 73 and 123 outwardly. This will shift the sampling tube 74 and filter tube 75 forwardly until the forward end 108 of tube 74 and outer end of cap screw 135 are against the formation 14. As the hydraulic pressure behind piston 123 in bore 125 continues to increase, the cap screw 135 will usually be urged against the formation 14 with such force that the washer 134 will fail and release the forward piston 130. Once the washer 134 fails, the filter tube 75 will slide forwardly in the sampling tube 74 until shoulder 127 engages shoulder 118 and the forward extremity 128 of the filter tube is inserted into the forward bore portion 117 of the sampling tube. The piston 130 will be shifted rearwardly a short distance. On the other hand, should the formation 14 be extremely soft, the cap screw 135 may merely burrow into the formation without fracturing the washer 134. This will still, however, allow the forward tube extremity 128 to enter the forward bore portion 117. In either event, the forward bore portion 117 will be essentially sealed by the forward extremity 128 of the filter tube 75 and shoulders 118 and 127 will be engaged.

Upon opening of the flow-line valve 66, the in-rushing formation fluids and sand particles 136 will quickly drive the forward piston 130 rearwardly in the bore 131 of the filter tube 75 to the position shown in FIG. 6 as the sample tube 74 and filter tube 75 are urged forwardly into the formation 14 to fill the void created by the loss of formation particles. If perchance the previously described step had not fractured the washer 134, the force of the pressure differential will be sufficient to cause the washer to fail.

137 at the rear of the bore 131. Thus, with the exception of a small amount of mud that might have been confined in the central opening 64 of the sealing member 62, the sand particles 136 will be isolated from the well control fluid and cannot become plugged by mud filling the 1f) voids between the particles. Moreover, the piston 130 will prevent commingling in the filter tube of the incoming connate fluids with the borehole fluids trapped in the sample-admitting means 23 when the bypass passage at 117 is closed.

It will be recognized that as the sand particles 136 are washed away, the tubes 74 and 75 must be urged for wardly to immediately fill the void created and prevent loss of sealing engagement by sealing member 62. Thus, should the sand particles 136 be rapidly washed away, it is possible that the hydraulic pressure could not build up fast enough through orifice 77 to continue driving the pistons 73 and 123. Accordingly, should this happen, the hydrostatic pressure will shift the accumulator piston 78 inwardly and maintain the hydraulic pressure behind pistons 73 and 123 at a sufficient level to continue driving the tubes 74 and 75 into the formation 14.

On the other hand, the orifice 77 and accumulator piston 78 and chamber 76 can be eliminated so that the hydraulic pressure in conduit 81 will always be maintained at a high level. This alternative configuration would, of course, actuate the sample-admitting means 23 as the wall-engaging means 24 urges the sealing member 62 against the formation 14.

As formation fluids continue to flow, they will enter the bore 131 of the filter tube 75 and be exhausted through the narrow longitudinal slits 129 into the intermediate bore portion of the sampling tube 74. The fluids will then flow from the annular space between the tubes 74 and 75 through the lateral ports 113 in the sampling tube 74 into the bore 95, and from there through the transverse passages 94 into the fluid conduit 67 leading to the sample-receiving chamber 27. It will be understood, of course, that as the formation fluids flow, the sand particles 136 carried along with the flow will, however, be trapped within the bore 131 of the filter tube 75 and be unable to pass through the narrow longitudinal slits 129 in the filter tube.

Thus, as seen in FIG. 6, the bore 131 of the filter tube 75 has filled with sand particles 136 so as to block the entrance of any additional particles. It will be further recognized that although displacement of these sand particles 136 creates a void in the formation 14, the continued hydraulic pressure on pistons 73 and 123 will shift the sampling tube 74 and filter tube 75 forwardly through the central opening 64 of the sealing member 62 to immediately fill the voided space as it is created and prevent loss of the sealing engagement of sealing member 62 due to the collapse of the unconsolidated formation.

Thus, in the position illustrated in FIG. 6, the sampling tube 74 has been shifted into the formation 14 a distance equivalent to the amount of voided space as the sand particles 136 were displaced therefrom and entered the bore 131 of the filter tube 75. It will be appreciated that, in this position, all flow must pass through the entrained sand particles 136 which will themselves act as a filtering media to further filter out very fine sand particles.

Also, as seen in FIG. 4, longitudinal slots 138 are cut through the external shoulder 127 of the filter tube 75. Although these slots 138 insure that fluids can flow across the co-engaged shoulders 118 and 127, they will also somewhat restrict the flow of the fluids. Thus, it will be appreciated that the pressure outside of the elongated slits 129 will always be greater than the pressure at the lateral ports 113. Accordingly, by providing this additional flow restriction, the slots 138 will reduce the pressure drop that is taken through the slits 129 themselves and thereby reduce the circumferential expansion of the elongated filter portion 124. This, of course, has the obvious advantage of allowing the slits 129 to open only as far as is needed for a particular flow condition and make the filter tube 75 more effective. Thus, under normal operation, the filter tube 75 will not necessarily expand until stopped by engaging the intermediate bore 115 of the sampling tube 74. Should one of the slits 129 become plugged, the pressure drop through the other slits will increase and cause the tube 75 to expand further. This further expansion may well allow whatever is plugging the slit 129 to be passed through the wider opening. Then, with the blocked opening cleared,.the pressure drop will decrease and the tube portion 124 can relax slightly and again constrict slits 129 to a narrower opening.

One the pressure transducer 89 indicates that the sample-receiving chamber 27 has filled, the hydraulic pressure in the main conduit 37 will be relieved as previously described by opening of valve 41. As the hydraulic fluid is exhausted into the dump chamber 38 and the pressureequalizing valve 40 opens, the hydrostatic pressure of the wellcontrol fluid will be imposed through conduits 52, ,65 and 94 into bores 95 and 125. Thus, the sample tube 74 and filter tube 75 will be withdrawn from the formation 14 and urged rearwardly asthe differential between the hydrostatic pressure increases over the slowly diminishing hydraulic pressure in the hydraulic system 25. Should, however, the sampling tube 74 and filter tube 75 in some manner. become lodged within the formation 14, it may be necessary to pull on the suspension cable 11 and snap the sampling tube 75 at one of the internal circumferential grooves 139 provided therein.

It should be noted that the sample-admitting means 23 is not limited for use with soft, unconsolidated formations. Should a formation be relatively firm or even so hard that little or no loose particles will be displaced, the forward end 108 of the sampling tube 74 will be urged against the formation and be sealingly engaged therewith for receiving connate samples. Thus, the sample-admitting means 23 is capable of service regardless of the condition of the formation. It should also be noted that whenever the sampling tube 74 penetrates an unconsolidated formation, the hydrostatic pressure will seal the loose particles around the tube. Thus, in a loose formation, the pad member 62 is an auxiliary seal. The sealing member 62 will, therefore, permit the sample-admitting means 23 to be used in hard or relatively. consolidated formations.

Accordingly, it will be appreciated from the foregoing description and illustrations that the present invention has provided new and improved means for obtaining fluid samples from particularly soft and unconsolidated earth formations at high flow rates that have not heretofore been possible. Inasmuch as any void that is created by displacement of sand from a formation is immediately filled by the sampling tube, no further cavitation will occur to wash away the formation from under the sealing member. Moreover, by eliminating the necessity of using a water cushion to regulate the flow rates at which samples are taken, fluid samples can be obtained much quicker and the apparatus will be substantially shorter than has been heretofore possible.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. Apparatus for use in a Well bore containing a column of well liquids comprising: packing means for sealing a section of a well bore; sample-admitting means on said packing means including an opening therein normally admitting well liquids and adapted to be placed in fluid communication with earth formations containing connate fluids; and selectively-operable means for closing said opening against further entrance of well liquids when said packing means are sealingly engaged with an earth formation and for isolating well liquids trapped within said sample-admitting means from such an earth formation.

2. Apparatus for use in a well bore containing a column of well liquids comprising sample-admitting means including an opening therein normally admitting well liquids and adapted to be placed in fluid communication with earth formations containing connate fluids; selectivelyopera'ble first means for closing said opening against further entrance of well liquids upon placement of said opening into communication with a formation; and selectively-operable second means for isolating such trapped well liquids without exposing an earth formation to such trapped liquids.

3. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an opening;

sample-collecting means including a sample-receiving chamber and normally-closed passage means between said opening and chamber; sample-admitting means including filtering means in said opening adapted to be placed in fluid communication with earth formations containing connate fluids; selectively-operable first means for closing said. opening against further entrance of well liquids upon placement of said opening into communication with a formation; and selectively-operable second means for placing said filtering means into fluid communication with an earth formation and said passage means.

4. Apparatus for use in a well bore containing a column of well liquids comprising: sample-collecting means in cluding a normally-closed sample-receiving chamber; sample-admitting means including a tubular member having a forward opening adapted to be placed in fluid communication with earth formations containing connate fluids, and another opening therein adapted to be in fluid communication with said sample-collecting means, and further including filtering means in said tubular member between its said openings, said filtering means having a discharge opening; means normally closing communication between said forward opening and said filtering means and responsive to opening of such communication for removing well liquids trapped in said filtering means through said discharge opening to prevent commingling of such liquids in said filtering means with incoming connate fluids.

5. Apparatus for use in a well bore containing a column of well liquids comprising: sample-collecting means including a normally-closed sample-receiving chamber; sample-admitting means including a tubular member having a forward opening adapted to be placed in fluid communication with earth formations containing connate,

fluids and another opening therein adapted to be placed in fluid communication with said sample-collecting means, said, sample-admitting means further including filtering means in said tubular member between its said openings; normally-open bypass means for bypassing well liquids around said filtering means; selectively-operable means for closing said bypass means; and means normally closing communication between said forward opening and said filtering means and responsive to opening of said chamber for removing well liquids trapped in said filter.- ing means to prevent commingling of such liquids in said filtering means with incoming connate fluids.

6. Apparatus for use in a well bore containing a colfluids and a rearward portion having a discharge opening;

filtering means in said tubular member between its said openings; normally-open bypass means for admitting well liquids into said tubular member and around said filtering means; selectively-operable means for closing said bypass means to prevent further entrance of well liquids and for placing said forward opening into fluid communication with an earth formation; and means normally closing communication between said forward opening and said filtering means and responsive to opening of said passage means for removing well liquids trapped in said filtering means through said discharge opening to prevent commingling therein of such trapped liquids with incoming connate fluids.

7. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-collecting means including a sample-receiving chamber and selectively-operable normally-closed passage means between said chamber and bore; sampleadmitting means including a tubular member movably disposed in said bore, said tubular member having a forward opening adapted to be sealingly engaged against earth formations containing connate fluids and a rearward portion having a discharge opening; filtering means in said tubular member between its said openings; selectively-operable means for placing said forward opening into fluid communication with an earth formation; means responsive to opening of said passage means for discharging well liquids trapped in said filtering means through said discharge opening to prevent commingling in said filtering means of such trapped liquids with incoming connate fluids; and means for advancing said tubular member into an earth formation whenever particles thereof are admitted into said tubular member.

8. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-collecting means including a sample-receiving chamber and selectively-operable normally-closed passage means between said chamber and bore; sampleadmitting means including a tubular member disposed in said bore, said tubular member having a forward opening adapted to be placed in fluid communication with earth formations containing connate fluids and a rearward portion having a discharge opening in communica tion with said bore; filtering means in said tubular member between said openings; normally-open bypass means for admitting well liquids into said bore around said fi'ltering means and into said tubular member behind said filtering means; selectively-operable means for closing said bypass means to prevent further entrance of well liquids and for placing said forward opening into fluid communication with an earth formation; barrier means in said filtering means normally closing communication between said forward opening and said filtering means and movable therefrom into said tubular member in response to opening of said passage means for displacing well liquid trapped in said filtering means through said discharge opening and into said chamber to prevent commingling of such trapped liquids with incoming connate fluids in said filtering means and for thereafter closing said discharge opening.

9. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-collecting means including a sample-receiving chamber and selectively-operable normally-closed passage means between said chamber and bore; sampleadmitting means including a tubular member movably disposed in said bore, said tubular member having a forward opening adapted to be placed in fluid communication with earth formations containing connate fluids, and a rearward portion having a discharge opening in communication with said bore; tubular filtering means in said tubular member between its said openings; normally-open bypass means for admitting well liquids into said bore around said filtering means and into said rearward portion of said tubular member; selectively-operable means for moving said tubular member forwardly to place said forward opening into fluid communication with an earth formation; means responsive to forward movement of said tubular member for closing said bypass means to prevent further entrance of well liquids; barrier means in said filtering means normally closing communication between said forward opening and said filtering means and movable therefrom into said tubular member in response to opening of said passage means for displacing well liquids trapped in said filtering means and said tubular member rearward portion through said discharge opening and into said chamber to prevent commingling of such trapped liquids with incoming connate fluids in said filtering means and for thereafter closing said discharge opening; and means for advancing said tubular member forwardly into said earth formation whenever particles thereof are displaced into said tubular member.

10. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore and adapted to be positioned adjacent earth formations containing connate fluids under pressure; sample-collecting means including a sample-receiving chamber at a pressure less than such formation pressures and selectively-operable normally-closed passage means between said chamber and a first location in said bore; sample-admitting means including a tubular member disposed in said bore, said tubular member having a forward opening adapted to be sealingly engaged against earth formations and a rearward portion having a discharge opening in communication with said bore; tubular filtering means having a lateral filter opening in said tubular member between its said openings, said lateral filter opening being enlargeable in response to an increased pressure differential thereacross; pressure-reducing means intermediate of said discharge opening and said filtering means for reducing pressure differential across said filter opening; normally-open bypass means for admitting well liquids into said bore around said filtering means and into said rearward portion of said tubular member; selectivelyoperable means for closing said bypass means to prevent further entrance of well liquids and for placing said forward opening into fluid communication with an earth formation; and barrier means in said filtering means normally closing communication between said forward opening and said filtering means and movable therefrom into said tubular member in response to opening of said passage means for dsiplacing well liquids trapped in said filtering means and rearward portion of said tubular member through said discharge opening and into said chamber to prevent commingling of such trapped liquids with incoming connate fluids in said filtering means and for thereafter closing said discharge opening.

11. The apparatus of claim 10 wherein said tubular member is movably disposed in said bore, said selectivelyoperable means are further adapted for moving said tubular member forwardly to place said forward opening into fluid communication with an earth formation and for closing said bypass means in response to such forward movement and further including means for advancing said tubular member forwardly into an earth formation whenever particles thereof are displaced into said tubular member.

12. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-collecting means including a sample-receiving chamber and selectively-operable normally-closed paS- sage means between said chamber and bore; sample-admitting means including a movable tubular member fluidly sealed in said bore and in tubular filter member disposed in said tubular member, said filter member having a forward opening, a lateral filter opening and a rearward discharge opening in communication with the annular space therearound, said tubular member having a passage in communication with said annular space and said bore and a forward opening adapted to be placed in fluid communication with earth formations containing connate fluids, said forward opening of said tubular member normally admitting well liquids into said annular space to bypass said filter member; selectively-operable means for moving said forward opening of said tubular member into fluid communication with an earth formation; means responsive to forward movement of said tubular member for closing said annular space forward of said lateral filter opening to prevent further entrance of well liquids; means responsive to opening of said passage means for discharging well liquids from said filter memher through said discharge opening to prevent commingling of well liquids with incoming connate fluids in said filter member and for thereafter closing said discharge opening; and means for simultaneously advancing said tubular and filter members forwardly into an earth formation whenever particles thereof are displaced into said filter member.

13. The apparatus of claim 12 further including means responsive to an increased pressure differential across said lateral filter opening for enlarging said filter opening; and pressure-reducing means in said annular space between said passage and said lateral filter opening for reducing the pressure differential across said filter opening.

14. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-collecting means including a sample-receiv ing chamber and selectively-operable normallyelosed passage means between said chamber and bore; sampleadmitting means including a first tubular member fluidly sealed and movably disposed in said bore, said first tubular member having a forward opening normally admitting rwell liquids and adapted to be sealingly engaged against earth formations containing connate fluids and a passage in communication with said bore, and a second tubular member slidably disposed within said first tubular member and sldable therein from a first position to a second position, said second tubular member having a plurality of elongated slits and a rearward portion having a discharge opening between the internal bore of said second member and the annular space therearound; means on said second tubular member for closing-off said annular space forwardly of said slits to prevent further entrance of well liquids whenever said second member is in said second position; first means selectively operable r for moving said first tubular member forwardly to place said forward opening into fiuid communication with an earth formation; second means selectively operablefor moving said second tubular member into said second position; and means responsive to opening of said passage means for removing well liquids trapped insaid internal bore of said second tubular member through said discharge opening to prevent commingling of such trapped liquids with incoming connate fluids in said tubular member and for thereafter closing said discharge opening.

15. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-collecting means including a sample-receiving chamber and selectively-operable normally-closed passage means between said chamber and bore; sampleadmitting means including a first tubular member fluidly sealed and in said bore, said first tubular member having a forward opening normally admitting well liquids and adapted to be sealingly engaged with earth formations containing connate fluids and a passage in communication with said bore, and a second tubular member having a forward opening and arranged to slide forwardly within said first tubular member from a first to a second position, said second tubular member having a forward portion adapted to be received within said first forward opening in said second position, a plurality of elongated slits and a rearward discharge opening between the internal bore of said secondmember and the annular space therearound; first means selectively operable for placing said forward opening of said first tubular member into fluid communication with an earth formation; hydraulic means selectively operable to move said second tubular member into said second position for closing said annular space forward of said slits to prevent further entrance of well liquids; and piston means slidably mounted in said second member and slidable inwardly therein in response to opening of said passage means for displacing well liquids trapped in said internal bore through said discharge opening into said chamber to prevent commingling of such trapped liquids incoming connate fluids in said sec- 16 0nd tubular member and for thereafter closing said discharge opening.

16. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-collecting means including a sample-receiving chamber and selectively-operable normally-closed passage means between said chamber and bore; sample-admitting means including a first tubular member fluidly sealed and movably disposed in said bore, said first tubular member having a forward opening normally admitting well liquids and adapted to be sealingly engaged with earth formations containing connate fluids and a passage in communication with said bore, and a second tubular member having a forward opening and arranged to slide forwardly within said first tubular member from a first to a second position, said second tubular member having a forward portion adapted to be received within said first forward opening in said second position, a plurality of elongated slits and a rearward discharge opening between the internal bore of said second member and the annular space therearound; first hydraulic means selectively operable for moving said first tubular member outwardly and placing its said forward opening into fluid communication with an earth formation; second hydraulic means selectively operable to move said second tubular member into said second position for closing said annular space forward of said slits to prevent further entrance of well liquids and for advancing said tubular members forwardly into an earth formation whenever particles thereof are displaced into said second tubular member; and piston means slidably mounted in said second member and slidable inwardly therein in response to opening of said passage means for displacing well liquids trapped in said discharge opening into said chamber to prevent commingling of such trapped liquids with incoming connate fluids in said second tubular member and for thereafter closing said discharge opening to capture such formation particles in said second tubular member.

17. The apparatus of claim 16 further including third hydraulic means responsive to the hydrostatic pressure of such well liquids and cooperatively connected to said first and second hydraulic means for also advancing said tubular members forwardly into said formation whenever particles thereof are displaced into said second tubular member.

18. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-admitting means including a first tubular member slidably mounted in said support bore, said first tubular member having a forward portion with a reduced bore therein normally admitting well liquids and adapted to be placed in fluid communication with earth formations and a rearward portion with an enlarged bore therein; first and second sealing means fluidly seal: ing said forward and rearward portions of said first tubular member within said support bore and defining therebetween a sample space; said first tubular member having first and second passages respectively communicating said enlarged bore with said sample space and the remainder of said support bore to the rear of said sealing means; a

second tubular member slidably mounted in said enlarged.

bore and adapted to slide forwardly therein to a forward position, said second tubular member having a closed rearward portion and an open forward portion adapted for reception within said reduced bore whenever said member is in said forward position to close said reduced bore and prevent further entrance of well liquids, said second tubular member having an intermediate portion with a plurality of generally longitudinal circumferentially-spaced elongated slits and a discharge opening to the rear thereof communicating the internal bore of said second tubular member with said enlarged bore; third sealing means fluidly sealing said second tubular member Within said enlarged bore intermediate of said first and second passages; a slidable pistonvmember fluidly sealed in said internal bore of said second tubular member and arranged to slide rearwardly therein to a position intermediate of said slits and discharge opening; means releasably securing said piston member in said open forward portion and releasable in response to a rearwardly directed force thereon; sample-collecting means coupled to said support including a sample-receiving chamber and selectively-operable normally-closed passage means between said chamber and sample space; and hydraulic means in communication with said remainder of said support bore and selectively operable for shifting said forward portion of said second tubular member into said reduced bore and for placing said forward portion of said first tubular member into fluid communication with an earth formation.

19. Apparatus for use in a well bore containing a column of well liquids comprising: a support having a bore with one end thereof open; packing means mounted on said support around said open end of said bore and adapted for sealing engagement with a wall of a well bore; sample-admitting means including a first tubular member slidably mounted in said support bore, wall-engaging means on said support and selectively operable for shifting said support toward a well bore wall to scalingly engage said packing means thereon; said first tubular member having a forward portion with a reduced bore therein normally admitting well liquids and adapted to be advanced through said packing means and placed in fluid communication with earth formations and a rearward portion with an enlarged bore therein; first and second sealing means fluidly sealing said forward and rearward portions of said first tubular member within said support bore and defining therebetween a sample space; said first tubular member having first and second passages respectively communicating said enlarged bore with said sample space and the remainder of said support bore to the rear of said sealing means; a second tubular member slidably mounted in said enlarged bore and adapted to slide forwardly therein to a forward position, said second tubular member having a closed rearward portion and an open forward portion adapted for reception within said reduced bore whenever said member is in said forward position to close said reduced bore and prevent further entrance of well liquids, said second tubular member having an intermediate portion with a plurality of generally longitudinal circumferentially-spaced elongated slits and a discharge opening to the rear thereof communicating the internal bore of said second tubular member with said enlarged bore; third sealing means fluidly sealing said second tubular member within said enlarged bore intermediate of said first and second passages; a first slidable piston member fluidly sealed in said internal bore of said second tubular member and arranged to slide rearwardly therein to a position intermediate of said slits and discharge opening; means releasably securing said piston member in said open forward portion and releasable in response to a rearwardly directed force thereon; sample-collecting means coupled to said support including a sample-receiving chamber and selectively-operable normally-closed passage means between said chamber and sample space; first hydraulic means including an actuator having a first hydraulic line in communication with said wall-engaging means and a second hydraulic line in communication with said remainder of said support bore and hydraulic fluid therein, said first hydraulic means being selectively operable for shifting said forward portion of said second tubular member into said reduced bore and for advancing said first tubular member through said packing means to place said forward portion of said first tubular member into fluid communication with an earth formation; a flow restricto-r in said second hydraulic line for retarding shifting of said tubular member until said packing means is sealingly engaged; and second hydraulic means responsive to the hydrostatic pressure of well liquids for advancing said tubular members forwardly into an earth formation whenever particles thereof are displaced into said second tubular member, said second hydraulic means including a second slidable piston member fluidly sealed in said remainder of said support bore and arranged to slide forwardly therein toward said tubular members and a third passage communicating the opposite side of said second piston member with such well liquids.

20. Apparatus for use in a well bore containing a column of well liquids comprising: a support having an open bore; sample-admitting means including a first tubular member slidably mounted in said support bore; said first tubular member having a forward portion with a reduced bore therein normally admitting well liquids and adapted to be placed in fluid communication with earth formations and a rearward portion with an enlarged bore therein; first and second sealing means fluidly sealing said forward and rearward portions of said first tubular member within said support bore and defining therebetween a sample space; said first tubular member having first and second passage respectively communicating said enlarged bore with said sample space and the remainder of said support bore to the rear of said sealing means; a second tubular member slidably mounted in said enlarged bore and adapted to slide forwardly therein to a forward position, said second tubular member having a closed rearward portion and an open forward portion adapted for reception within said reduced bore whenever said member is in said forward position to close said reduced bore and prevent further entrance of well liquids, said second tubular member having an expansible intermediate portion with a plurality of generally longitudinal circumferentially-spaced elongated slits adapted to widen upon expansion of said intermediate portion by an increased pressure differential across said slits, and a discharge opening to the rear thereof communicating the internal bore of said second tubular member with said enlarged bore; third sealing means fluidly sealing said second tubular member within said enlarged bore intermediate of said first and second passages; pressure-reducing means in said enlarged bore between said slits and discharge opening of said second tubular member for reducing a pressure differential across said slits; a slidable piston member fluidly sealed in said internal bore of said second tubular member and arranged to slide rearwardly therein to a position intermediate of said slits and discharge opening; means releasably securing said piston member in said open forward portion and releasable in response to a rearwardly directed force thereon; samplecollecting means coupled to said support including a sample-receiving chamber and selectively-operable normallyclosed passage means between said chamber and sample space; and hydraulic means in communication with said remainder of said support bore and selectively operable for shifting said forward portion of said second tubular member into said reduced bore and for placing said forward portion of said first tubular member into fluid communication with an earth formation.

References Cited UNITED STATES PATENTS 2,613,747 10/1952 West 166100 2,903,069 9/1959 Lebourg et a1 166-100 2,905,247 9/1959 Vestermark 166-100 2,965,176 12/1960 Brieger et al. 166-100 X 2,982,130 5/1961 McMahan 166100 X 3,173,485 3/1965 Bretzke 166100 ERNEST R. PURSER, Primary Examiner.

DAVID H. BROWN, Examiner. 

1. APPARATUS FOR USE IN A WELL BORE CONTAINING A COLUMN OF WELL LIQUIDS COMPRISING: PACKING MEANS FOR SEALING A SECTION OF A WELL BORE; SAMPLE-ADMITTING MEANS ON SAID PACKING MEANS INCLUDING AN OPENING THEREIN NORMALLY ADMITTING WELL LIQUIDS AND ADAPTED TO BE PLACED IN FLUID COMMUNICATION WITH EARTH FORMATIONS CONTAINING CONNATE FLUIDS; AND SELECTIVELY-OPERABLE MEANS FOR CLOSING SAID OPENING AGAINST FURTHER ENTRANCE ON WELL LIQUIDS WHEN SAID PACKING MEANS ARE SEALINGLY ENGAGED WITH AN EARTH FORMATION AND FOR ISOLATING WELL LIQUIDS TRAPPED WITHIN SAID SMAPLE-ADMITTING MEANS FROM SUCH AN EARTH FORMATION. 